Vaned projectile



March 3o, 1942.,Y J. WAUTERS 2,315,145

' VANED PROJEGTILE Filed July 24. 1939 Patented Mar. 3Q, i943 VANED PROJECTLE Application July 24, 1939, Serial No'. 286,278 in Luxemburg July30, 1938 5 Claims.

The present invention relates to improvements in vaned projectiles andmore especially to those intended to be fired from muzzle-loaded guns ormortars.

It is a known fact that, in order to increase the steadiness of suchprojectiles along their trajectory, it is advisable to set the centre ofgravity as far forward as possible. With this object in view it has beenproposed to make the vanes or aluminium or some other substance lighterthan the body of the shell which is usually made of cast iron or steel.

When the projectile is provided at the rear with a tail containing thepropelling charge, a known means of setting the centre of gravityforwards consists in arranging said tail in such a way that it maybecome detached from the shell when the shot is fired.

The improvements according to the invention apply more especially to adetachable tail vaned projectile of this nature and are remarkable, inparticular, owing 'to the fact that friction means are applied totemporarily X said tail to said body up to the moment of firing.According to an embodiment of the invention, said `charge-bearing tailis provided with a conical end capable of engaging with acorrespondingly shaped recess provided at the rear of the body; the tailbeing moreover provided with a flange shaped in such a way that when thetail is rotated in its recess, increased friction is applied on the finsof the vane system so as to secure the tail on the shell until it isred. This method of attachment ensures the correct release of the tailin the gun itself and its ejection immediately after the projectile hasissued from the muzzle, through the action of the sudden depressionwhich then occurs in the bore.

According to another peculiarity of the invention, the contour of theportion of the projectile forward of the main diameter and the contourof the fuze are'of a shape such, that along a length comprised betweenone and a half and three times the calibre, the combination forms aconcavo-convex contour in which the front concave portion and the rearconvex portionmerge tangentially.

Experience shows that this peculiar form of the front end of theprojectile considerably facilitat-es its travel through the air byreducing drag; it should be noted that said result has been registeredwhen ring at initial speeds less than those ci" sound for whichprojectiles with a more stubby nose: ovoid, elliptic or parabolicz hadhitherto been considered as being best.

A further feature of the invention is that the concave-convex portion ofthe projectile merges directly with the rear portion of decreasingdiameter and the length of the rear portion, up to the point of originof the vanes, is between 1 and 3 calibres.

The length of the vanes themselves varies between three quarters of thecalibre and one and a half calibres.

In one form of embodiment, the vanes are supported by a ring secured tothe base 0f the shell and provided with a conical portion into which thecharge bearing tail is fitted.

A further feature of the invention is that the gun-powder relay whichensures the ignition of the detonator is separated from it by a thinstamped gas-check cup or sheath the edges of Which, folded back on aplastic washer, are set in a groove of the eye of the projectile.

With this arrangement, the usual screwed relay sheath and sheath headare suppressed which relieves the projectile of an appreciable deadweight load.

Other advantages and peculiarities of the invention will appear in thefollowing description.

In the attached drawing which is given merely as an example:

Figure 1 is an axial section of a projectile embodying the improvementsaccording to the invention;

Figure 2 is an end view;

Figure 3 is a view similar to that in Fig. 2 showing the appearance ofthe rear of the shell after the tail has been discarded;

Figure 4 is a plan view of an additional proy pelling charge.

According to the example illustrated, the projectile comprises a body ito the front portion of which is fitted a fuse 2 while the rear is ttedwith a set or" vanes 3 solid with a ring li which is screwed ont-o athreaded teat 5 provided on the base.

The vane blades 3 are preferably slightly inclined with respect to thelongitudinal axis of the projectile (less than 4 degrees) in order toimpart to it a very slow gyratory motion along its trajectory.

Ring 4 is provided with a conical recess into which penetrates thecorrespondingly shaped end l of a charge-carrying tail B. A cartridge 9,or some other propelling charge is introduced into the charge-carryingtail for the purpose of ig-A niting additional charges l of annularconstruction, as shown in Figure fl, through radial holes I9,v

A varying number of said relays II is positioned on tail 8 according tothe range desired when this cannot be obtained by means of the cartridgealone.

A ange I2 (Figs. l and 2), the outer contour of which assumes the formof eccentric sectors I3 engaging with the inner edges of vanes I3, issecured to tail 8 by welding I2'a or other means. In the presentexample, the distance in a plane perpendicular to the axis of the tailof said axis to the several points of the outline of each sectorincreases, in the case of each one of them, in a counter-clockwisedirection. It is therefore suicient to rotate the tail in the oppositedirection to determine an increasing pressure on vanes 3, by means offlange I2, which pressure is utilised to hold the tail in position.Flange I2 bears against a correspondingly shaped cut vIII (Fig. 3)provided in blades 3 of the set of vanes.

Forward of the main diameter, the projectile and its fuse are shaped insuch a manner that their outline assumes a concave contour I5 in frontand a convex contour IS at the rear, the concave and convex portionsmerging tangentially at point I'I, their combined length being betweenone and a half and three calibres.

On the example shown in the drawing, the total length of the frontportion up to the main diameter is approximately 2 calibres and theinexion point I1 is positioned at approximately 1 calibre from the maindiameter. At the rear of said main diameter, the extension I 8 oftheprojectile is of decreasing diameter, the length of which measured up tothe point of origin of the varies is between l and 3 calibres. The curveof said rear portion merges tangentially with that of the fore part inproximity to the main diameter.

The length of the vanes is between 0.75 and 1.5 calibres. The blades maybe comparatively `thin and may be suitably shaped to reduce drag.

Slightly to the rear of the main diameter the projectile is provided, inthe known manner, with a groove I9 housing an expanding leak-proofdriving band 29 (a split brass ring for instance).

The fuse, the mechanism of which is not shown, causes the ignition of adetonator 22, which consists of an explosive more powerful than thecharge of the projectile, through a secondary primer 23 and a conicalrelay 24 which is separated from the detonator by a thin stamped cup orsheath 25 to prevent leakage. The edges 26 are folded over a plasticwasher 2l, and are set in a groove 23 of the eye of the shell.

When the fuse 2 is screwed home, it bears on` rim 26 of sheath 25 whichit secures in position. Secondary primer 23 and relay 24 can withadvantage be positioned inea block 29 rotatably fitted in the body ofthe fuse.

Two channels are drilled through said block, one of which, 39, is emptywhile the other, 3|, contains a pastille 32 of delay-action compound.According to the position given to block 29, one or other of saidchannels is brought into communication with the firing channel 33 of thefuse so that instantaneous or delayed ire is obtained on impact.

When the projectile is fired from a muzzle loaded smooth bore mortar,the barrel being inclined with respect to the horizon by the desiredangle, the projectile, fitted with its cartridge 9 and, in case of need,with its relays I I, is inserted into it. The shell slides into the boreby gravity and, on reaching the bottom, the cartridge strikes the ringpin which protrudes from the breech and deiiagrates and ignites relaysII through holes I0, the gases of the latter combining with those of themain charge to provide propulsion. The driving band 29 rising along rampI9 provides a leak-proof joint between the bore and the shell. The tailseparates from the projectile upon firing. In case of need, holes mightbe drilled through flange I2 to give the required intensity to theejecting effect.

The centre of gravity of the projectile, when relieved of its tail, ismoved considerably forward of the position it occupies in the xed tailprojectiles generally in use up to the present. Its steadiness isappreciably improved thereby, thus increasing the accuracy of fire to agreat extent.

The absence of a tail lalso contributes t0 the flight of the shell asthe air stream can close freely between the vanes. On the other hand,the capacity in explosive and the offensive value remain the same as inthe usual fixed tail type.

The vanes which are slightly inclined with respect to the longitudinalaxis of the projectile also contribute to greater precision by remedyingany defects in the symmetry of the shell which are compensated by itsslow rotational speed along the trajectory.

The reduction in weight of the projectile procures a reduction in theenergy of the recoil which is usually applied to a base plate laid onthe ground. It is therefore possible to make this plate lighter andlsmaller which facilitates the transportation thereof.

It should be noted that the vane assembly and the removable tail abovedescribed can be iitted to existing projectiles in lieu of the usualfixed tail with a View to improving their ballistic qualities.

The iniiexed curvature of point I5, i5 ensures percussion even under lowangles of impact at which percussion could not be obtained with a convexor more stubby front portion.

It is to be understood that the invention has been shown and describedonly as an example and that it is capable of various modifications swithout departing from the spirit of the invention.

I claim:

l. A projectile comprising a body, a tail for carrying a propellingcharge, means for centering :said tail along the longitudinal axis ofsaid body and rearwardly of said body, a radially extending ange solidkwith said tail, stabilizing blades' iixed at the rear of said body, theouter contour of said ange assuming the iorm of eccentric sectorsengaging the inner edges of the blades and adapted to exert anincreasing pressure thereon when the tail is rotated in an appropriatedirection about its longitudinal axis whereby the tail is temporarilyixed to the body, said tail being adapted to be detached from the shellatrin'g.

2. A projectile comprising a body presenting externally at its rear endan inwardly tapering conical recess, a tail for carrying a propellingcharge, said tail vhaving a conical front end corresponding in shape tothe conical recess of the body and engaging that recess, stabilizingblades fixed atthe rear end of said body, a flange solid with said tail,the outer contour of said ange assuming the form of eccentric sectorsengaging the inner edges 0f the blades and adapted to exert anincreasing pressure thereon when the tail is rotated in an appropriatedirection in the recess, said tail being `adapted to be detached fromthe shell at ring.

3. A projectile comprising a body, a ring fixed to the rear end ofsaidbody and formed with an inwardly tapering conical recess, externallyextending stabilizing blades on said ring, a tail for carrying apropelling charge, said tail having a conical front end corresponding inshape to the conical recess in the ring and engaging said recess, a angesolid with said tail, the outer contour of said flange assuming the formof eccentric sectors engaging the inner edges of the blades and adaptedto exert an increasing pressure thereon when the tail is rotated in anappropriate direction about, its longitudinal axis whereby the tail istemporarily xed to the body, said tail being adapted to be detached fromthe shell at ring.

4. A projectile comprising a body having stalbilizing blades xedadjacent the rear end thereof, a tail structure carrying a propellingcharge and disposed axially of said body and inwardly from the inneredges of the blades, and means including cam-shaped surfaces projectingsubstantially radially from the tail structure and engageable withincreasing pressure on the inner edges of the blades upon appropriaterotation of the tail structure for temporarily fixing the said tailstructure to said body up to the moment of ring whereby to permit thetail structure to be detached from the body at firing.

5. A projecile comprising a body having stabilizing blades xed adjacentthe rear end thereof, a tail structure carrying a propelling charge anddisposed axially of said body and inwardly from the inner edges of theblades, the inner edges of said blades being provided with cut-outportions, and flange means extending substantially radially from saidtail structure and having cam-shaped surfaces engageable with thecut-out portions on said blades for temporarily fixing said tailstructure to said body up to the moment of ring whereby to permit thetail structure to be detached from the body at iiring.

JEAN WAUTERS.

